Fluid heater cleaners



April 12, 1960 w. MccoLL FLUID HEATER CLEANERS 5 Sheets-Sheet 1 FiledNov. 4, 1955 MS. Mm. Nw EN pr 12, 1960 w. MccoLl. 2,932,053

FLUID HEATER cLEANERs I Fiied Nov. 4. 1955 3 sheets-sheet 2 April l2,1960 w. MccoLL FLUID HEATER CLEANERS 3 Sheets-Sheet 3 Filed Nov. 4. 1955l I t /ygueeaZ W, aryl/7m. Attorneys.

United States Patent FLUID HEATER CLEANERS William McColl, London,England, assignor to Diamond Power Specialty Corporation, Lancaster,Ohio, a corporation of Ohio Application November 4, 1955, Serial No.544,942

Claims priority, application Great Britain November 4, 1954 11 Claims.(Cl. 15-317) This invention relates to iluid heater cleaners. In largepresent day tubulous boilers diicult problems arise in maintaining thecleanliness of the outer surfaces of tubes which are arranged in banksof substantial depth and subjected to high gas temperatures. Theinvention is particularly concerned with a form of cleaner adapted foruse in connection with such tube banks and having a nozzle tube axiallyreciprocable to advance the tube from -a retracted position and towithdraw the tube to the retracted position and connected to a carriagemovable to and fro along a track and operating mechanism forreciprocating the nozzle tube and carriage.

VIt has been proposed to effect the recprocatory movement of the nozzletube by means of a reversible motor coupled to an endless chain having arun which extends ina direction parallel to the nozzle tube and iscoupled to the nozzle tube, whereby reversal of the direction ofrotation of the motor effects reversal of the direction ofreciprocation. When, as is usual, the cleaner constitutes one of aseries of cleaners adapted to operate in sequence under the control ofan automatic control system, the necessity of effecting reversal of themotor has resulted in complication of the control system. In

this prior proposal, a separate driving motor was pro-v vided to obtainunidirectional rotation of the nozzle tube despite reversal of thedirection of reciprocation.

An object of the present invention is the provision of means foreffecting axial reciprocation of the nozzle tube and utilising aunidirectionally rotating motor. By the present invention a single-motormay be utilised to provide both unidirectional rotation of the nozzletube and reciprocation of the nozzle tube.

According to the present invention, in a iluid heater cleaner having anozzle tube axially reciprocable to advance the tube from a retractedposition and to withdraw the tube to the retracted position andconnected to a carriage movable to and fro along a track and operatingmechanism for reciprocating the nozzle tube and carriage, the operatingmechanism includes endless flexible means having two runs extendinglongitudinally of the track and coupling means adapted when the endlessflexible means is driven unidirectionally automatically to couple thecarriage to one run for controlled movement of the carriage and nozzletube in one direction and to the other run for controlled movement ofthe carriage and blower tube in the opposite direction.

The invention will now be described, by way of example, with referenceto the accompanying diagrammatic drawings, in which: Y

Figure l is a partly broken away sectional side elevation o'f a lluidheater cleaner, taken on the line I-I of Figure 2 and as viewed in thedirection indicated by the arrows;,and shows a nozzle tube thereof in aposition adjacent an extreme forward operating position; A

Figure 2 is a sectional front elevation taken on the line Il-II vofFigure 1, as viewed' in the direction indi# Vcated by the arrows;

ICC

Figure 3 is a sectional plan view taken on the line III-III of Figure 1;

Figure 4 is a sectional fragmentary plan view of parts of the cleanershown in Figure 3, but with moving parts thereof shown in a rearwardextreme operative position; and

Figure 5 is a front elevation of a driving abutment taken on the lineV-V of Figure l and as viewed in the direc# tion indicated by thearrows. Y

The cleaner illustrated includes a nozzle tube 1 which may be advancedthrough an aperture in a wall 2 of the casing of a tubulous fluid heaterwith which the cleaner is associated from a retracted position to anadvanced position slightly forward of the position shown in Figure l. Aforward end of the nozzle tube (not shown) is provided with nozzleapertures one vof which is arranged to project lluid at right angles tothe axis of the nozzle tube and another of which is arranged to projectuid forwardly at an angle to the said axis, the nozzles being soarranged that in operation the forces acting transversely of the nozzletube due to the discharges from the nozzles are substantially balanced.While the nozzle tube is in the retracted position, the forward end issurrounded by a wall box 4 which serves to shield the forward end of thetube.

The nozzle tube 1 is supported immediately outside the wall 2 upon abracket (not shown) which is adapted to permit free rotation of the tube1 and at its rearward end 1a is mounted in a carriage 6. Carriage 6 issuspended from a track plate 7 by four anged upper guide rollers 8rotatably mounted upon pivot pins 9 secured to the carriage 6. The trackplate 7 is secured to and wider than the lower ange 10 of an I-beam 11,which is mounted on and which extends normally outwardly from the wall 2parallel to, above and beyond the retracted nozzle tube 1. Four lowerguide rollers A12 mounted upon pivot pins 13 secured to the carriage aredisposed below the track plate 7 in engagement with its lower surface7a.

The nozzle tube 1, which is of substantial length, for example 25 feetlong, is telescopically arranged with respect to a coaxial stationarytube 14 for the supply of cleaning fluid supplied under substantialpressure, the rear end 1a of the nozzle tube 1 being secured to astuiing box member 15 arranged to make a pressure tight seal between thetubes 1 and 14. The rearward end of the supply tube 14 is connected to avalve chest (not shown) which may be of the form shown in thespecification of British Patent No. 636,052.

The actual mounting for the nozzle tube 1 in the carriage 6 is notdetailed in the drawings, but takes the form of a journal and thrustbearing 16 which engages the outside surface of the stuiilng box member15 to permit the latter to rotate relatively to the carriage about theaxis of the tube 1 and to inhibit axial movement of the member 15 andthus the tube 1 through the carriage.

The forward end of the stuffing box member 15 is formed as a bevel gearwheel 17 which coacts with a second bevel gear wheel 18 formed with anaxle 19 tted into a bearing 20 in oor 21 of the carriage 6 and formed onits upper side with a spur gear wheel 22. Also mounted in the carriageare two vertical shafts 23 and 24 disposed forwardly of the bearing 20and one on either side of the spur gear wheel 22. Spur gear wheels 25and 26 respectively mounted on the two shafts 23 and 24 are arrangedoperatively to engage the gear wheel 22 and the two shafts respectivelycarry at their upper ends vertical shafts 132 and 33 rotatably mountedin the carfia'ge' and respectively provided at their upper Iends withactuating wheel chain sprockets 34 and 35 keyed to the shafts. Alsomounted on the carriage 6 are four chain sprocket jockey. pulley wheels36, thev six chain sprockets 'all being arranged with 'their teeth inthe same horizontal plane.

The free-wheel devices 30 and 31 are both of the same hand, such thatwhen one of the chain sprockets 34 and'35 `is rotated in a clockwisedirection (as viewed from above) Vthe .intermediate bevel gear wheel 18rotates in a counterclockwise direction causing the nozzle tube' 1 torotate in a clockwise direction, as viewed in Figure 2. .This rotationis quite independent of whether thesecond 'of the chain sprockets 34 and35 is caused to rotate in either direction or is held against rotation.

` Endless flexible means in the form of `an endless chain 50 arearranged to .extend horizontally along and below the track plate 7 andthrough the upper part of the carriage 6,.the.'chain being disposed onthe outward sides 'ofthetwo sprockets34 and 35 andon the inward sidesofthe four `jockey wheels 36, as is shown most clearly in Figure 3. Atthe rear end of the track plate 7 a bracket 51 is secured to the I-beam11 and supports a rotatablymounted idler chain `sprocket wheel 52 and arotatably mounted chain sprocket jockey pulley wheel v53, the sprockets52 and 53 being arranged with their teethin'tne .same horizontal planeas are the teeth of theV sprockets 34, 35 and 36. The chain 50 is solapped about the sprockets 52 and 53 that the advancing run 54 and theYreturning run 55 ofthe. chain are closely spaced together, as shown inFigure 3.

At the forward end of the track plate 7 a bracket 60 is secured to theI-beam 11 and supports a driving sprocket wheel- 61 and a. chainsprocket` pulley wheel '62 arranged with their teeth in the same planeas thev teeth of theV two sprockets 52 and 53. The `driving sprocketwheel 61'is xedly mounted upon a driving shaft 63 coupled to the outputshaft 64 of a combined electric motor and gear box unit 65 which issuitably mounted onthe I-beam above the Vsprocket V61. The centres ofthe driving sprocket wheel 61 and the idler sprocket wheel 52 arerespectively off-set on opposite sides of the centre line of the track,the jockey .wheels 53, '62 being on opposite sides of the two runs ofthe chain.V

vBracket 60 is formed with a projection 60a adapted to engage thecarriage 6 and so limit forward movement of the carriage in a positivemanner.

AThe chain 50 is a roller chain comprising links having side^pl`atesconnected by pivot pinsthat serve to couple adjacent links together in ahinged manner, the pins being provided with rotatable rollers. One ofthe chain links is provided with a driving device 66 includingV a pivotpin 67 that extends at each end laterally of the chain beyond theassociated side plates a distance equal to4 about one third of thelength of 'the standard pivot pins and a roller 63 carried upon each endof the pin vThe carriage is provided with two driving abutments adaptedfor engagement by the'driving device66, a forward driving abutment 70provided on a forward projection 71 of the carriage 6 and a rearwarddriving abutment 72 provided on a rearward projection'73 of thecarriage'6. Each driving abutment 70 and 72 is in the form of a forkwhich embraces the outer side and top and bottom faces of the associatedadvancing run 54 or returning run 55 of the chain, and the bifurcationsof which are arranged respectively to engage the two rollers 68, asshown for the forward driving abutments 7()` and advancing run 54 inFigure'S. It will be seen in' that ligure that there is a considerableclearance above and below the chain, but this clearance is much lessthan the height of the'rollers 68. t

'The'chain 50 is also 4provided withai brakingdevice 75 similar to thedriving device 66 and` comprising a pivot pin' 76 and two rollers 77mounted upon the pin, the ro1lers"`77 being Iof much smaller width'thantherollers 68 and the whole braking device being of such size that itcan pass through the forked driving abutments" 70 'and The carriage 6 isprovided adjacent its rearward end with a braking abutment inthe form ofa fork arranged with its bifurcations extending respectively above andbelow the advancing run 54 of the chain 50 from a plate 82 mounted onthe carriage 6 and extending downwardlyfrom the top of the carriagebetween the two runs 54 and 55 of the chain. Unlike the two'drivingabutments, this abutment 80 embraces the chain closely so that therollers 77-of the braking device 75 may effectively engage the brakingabutment.

The carriage 6 is provided with a rearwardly extending arm (not shown)arranged to actuate a stop valve that controls the supply of cleaningHuid to the rear end of stationary tube 14; during rearward movement ofthe carriage the arm actuates the stop valveto discontinue the supply ofcleaning fluid before the nozzle tube reaches its rearward, fullyretracted, position. Such. an arrangement is' described and illustratedin the specification of British Patent No.v 636,052.

)Alimit switch (not detailed) is mounted on'the track plate'7 where itwill be engaged by the driving device 66 as it approaches the positionshown in Figure 4, and the indication given by engagement of the drivingdevice with the limit switch is supplied to a suitable control systemwhich will determine whether motor unit 65Y is to remain energised or tobecome de-energised. The rotational inertia of the motor unit will causethe driving device 66 todisengage from the limit switch before'the chaincomes to rest.

During periods when the fluid heater cleaner is not in use, the nozzletube is in a fully retracted position in which the forward end of thenozzle tube lies within the wall box 4 and the rearward end of thecarriage lies in the position indicated in Figure 4. The stop valvecontrolling the supply of cleaning fluid is closed and the drivingdevice 66 lies in the position shown in Figure 4 or in some nearbyposition in the advancing run 54 ofthe chain 50.

To initiate operation of the cleaner, electrical power is supplied tothe electric motor unit 65, which commences to rotate and moves thechain 50 in a clockwise direction as seen from above. At first thecarriage 6 will remain stationary and the-only effect of the movementofthe chain will be to cause rotation of the actuating wheel sprockets34 and 35. Since sprocket 34 is caused to rotate in a clockwisedirection, it will be effectivethrough thefree-wheel device 30 to causerotation of the bevel gear wheel 18 in a counterclockwise direction andto cause the bevel gear wheelV 17 and the nozzle tube 1 to rotate in aclockwise direction, as viewed in.Figure.2. The actuating wheel sprocket35 rotates also. in a clockwise direction and through the associatedfree-wheel device 31 assists in the driving of bevel gear wheel18.

As the chain 50 rotates, the driving device 66 Vmoves from the positionshown in Figure 4 forwardly with the advancing run 54 through thecarriage 6 until it engages the forward driving abutment'70, whereuponthe carriage. moves forward with, and at the same speed as, the chain50. Immediately before the carriage is thus coupled to the chain, thebraking device 75 passes round the vjockey sprocket 53 and assumes aposition relative to the carriage immediately in front of the brakingabutment 80 i.e. as shown in Figure 3. Y

Sincethe 'carriage is now moving forwardly at .the speedof the .chain50, its velocity relative to the returning run 55 of the chain is nowdoubled, and as a. direct result the speed of rotation of the nozzletube 1 by the actuating wheel 34 and free-wheel device30 is alsodoubled. Actuating wheel 35 yduring this .movement is unc'oupled fromthe nozzle tube 1 byaction of the :freewheel device 31,

Aftera predetermined forward travel of the carriage 6, opening of thestop valve which controls the supply of cleaning fluid is eected by thestop valve actuating J arm, referred to above, mounted upon the movingcarriage, and cleaning Huid under substantial pressure is admitted tothe interior of the nozzle tube 1 and is discharged through the nozzlesprovided at and near the forward end thereof.

Once this pressure is applied to the interior of the nozzle tube 1 thenozzle tube is biased forwardly with the carriage relative to the ixedtube 14 by the unbalanced pressure acting upon the forward end of thenozzle tube, and the subsequent action of the chain druing the remainderof the forward movement of the nozzle tube 1 depends upon whether thisbiasing force is greater than or less than the frictional forces whichact on'the nozzle tube and tend to retard its forward movement relativeto the tube 14. For example, a given Huid heater cleaner may, due towear of the packing in the stufling box member 15 and due to theaccumulation of deposits on the outer extremities of the nozzle tube 1`and the fouling of such deposits with supporting bearingsprovided on thetubes of the fluid heater, at differentr times in its working lifebehave in different ways.

If the pressure inside the nozzle tube 1 is insufficient to cause thenozzle tube to advance along the tube 14, then controlled forwardmovement of the nozzle tube will be eected by engagement of the drivingdevice 66 with the forward driving abutment 70 until the driving devicepasses round the, driving sprocket wheel 61 and so moves sidewardly outof engagement with the abutment 7 0.

If the pressure inside the nozzle-tube 1 is suflicient to cause thenozzle tube to advance along the tube 14, after a very short relativemovement the braking abutment S0 comes into contact with braking device75. The braking device 75 is then effective to, cause controlled forwardmovement of the carriage and blower tube until the projection 60a ofbracket 60 engages the forward projection 71 ofthe carriage 6 in orderto terminate forward movement of the carriage at a position a shortdistance beyond that position at which the driving device 66 disengagesthe driving abutment 70. Continued forward vmovement of the chain willthen cause the braking device to become disengaged from the brakingabutment 80.

Upon termination lof the forward movement of the carriage 6 and thenozzle tube, the movement of the chain 50 is still effective to causerotation of the nozzle tube 1, but since the carriage is now at rest,the speed of rotation of the nozzle tube is reduced to half the speed ofrotation obtained during forward movement of the nozzle tube.

The driving device 66 enters the returning run 55 of the chain and aftera short delay engages the rearward driving abutment 72 to couple thecarriage 6 to the returning runof the chain and so effect rearwardmovement of the carriage and nozzle tube. During this delay period, thebraking device ,reaches and passes freely through the forward drivingabutment 70 and also-passes round the driving Wheel 61.

During rearward movement of the carriage, it is at restV relative to thereturning run S5 and as a result its velocity relative to the advancingrun 54 of the chain is doubled, so that the speed of rotation, eected bythe chain through the actuating wheel 35 and the free-wheel device 31,of the blower tube 1 is doubled. in the arrangement shown, in which thechain sprockets 34 and ,35g have equal numbers of teeth, the speeds ofrotation of the nozzle tube during forward and rearward movement areequal to one another and are'equal to twice the speed of rotation whichobtains during the dwell of the nozzle tube while in the forwardposition, but if these sprockets had unequal numbers of teeth, the speedof rotation during the forward travel would Vbe diiferentfrom the speedof rotation during the rearward travel.

As the carriage approaches the rearward position indithe Yabutmentsthereon.

cated in Figure 4, the stop valve is operated by the arm on the carriageto stop the supply of cleaning fluid to the nozzle tube. At the rearwardposition of the carriage, the driving device 66 passes round the idlerwheel 52 andfso disengages from the rearward driving abutment 72,.Asrwill be clear from Figure 4, the braking abutment is so set inrelation to the rearward driving abutment that the devices are able topass round the jockey wheel 53 Withoutengagement with the brakingabutment.

The limit switch Ais actuated by thedriving device 66 as it approachesthe position shown Ain Figure 4 and the Vassociated controlsystem willdetermine whether the cleaning-operation is'to continue or to terminate.If the electric motor unit 65 is allowed to remain energised by thecontrol system, the cycle of operations will be repeated, and the nozzletube 1 will re-enter the uid heater, -pause in the forward position, andbe retracted. ""If desired, the period of the forward dwell may bereduced or substantially eliminated by the provision of a plurality ofdriving devices so arranged that movement of one driving device awayfrom the forward driving abutment is followed in quick succession byengagement of Va second driving device with the rearward drivingabutment, the second driving device being positioned on the chain 'ashort distancev in advance of the first driving device and being sodimensioned that it is able to pass the forward driving abutment. Thusthe second driving device mayextend laterally of the chain to a smallerextent than the lirst driving device, the fork of the forward drivingabutment being designed to permit passage ofthe second'driving devicebut to prevent passage of the first driving device, whilst the fork ofthe rearward driving abutment is designed to prevent passage of thewhenat the end of the advancement of the nozzle tube thefirst drivingdevice moves sidewardly to disengage from the forward" driving abutment,'the second driving device is already in the returning run of the chainand quickly engages the rearward driving abutment so that the carriageis driven rearwardly.

The' 4ccJnst'ructions of iluid heater cleaner described above haveseveral advantageous features. Thus, since the motor for effectingactuation of the nozzle tube is a fixture adjacent the wall of the fluidheater it is no longer necessary to provide a gallery for aording readyaccess to working parts which extend over the total length of the trackplateand the need for a flexible trailing power lead to a 'motor mountedon and moving with the carriage is eliminated. Although only a singledriving motor is provided, reciprocating movement of the nozzle tubeisaccompanied by unidirectional rotation of the nozzle tube., As aresult, during withdrawal, the jets of cleaning fluid'sweep over ahelical path which is a different path from the helical path sweptduring the advancement of the nozzle tube. Since the cleaning action iseffective both during the advancement and during the retraction of thenozzle tube, asubstantial saving of cleaning fluid may be obtained. Thejockey pulleys 36 serve to cause each lrunfof the chain to embrace asuitable arc of the associated actuating wheel and maintain properlateral posi- .tioning of the associated run to the forward and rearwardsides of the'actuating wheel relatively to the carriage and Furthermore,the driving abutmentsim'ay be arranged to give a desired dwell period ofthe nozzle tube in its forward position in order that tubes ofthe uidheater beyond the end of the nozzle tube may be effectively cleaned.

The braking device may be omitted and the driving device serve also as abraking device which engages the braking abutment to limit uncontrolledforward movement, but the preferred construction described has theadvantage that appreciable unchecked movement of the nozzle tube underthe inuence of the cleaning iiuid pressure is avoided.

- I claim:

1. -Ina fluid heater cleaner having a nozzle tube axially reciprocableto advance the tube vfrom a retracted'position and to withdraw the tubetothe retractedv position and connected to a carriage movable to and froalong a track and operating mechanism for reciprocably driving thenozzle tube "and carriage substantiallyhorizontally in both directions,wherein the operating mechanism includes endless flexible'means havingtwo runs extending longitudinally of the track, unidirectional drivingmeans for actuating said flexible means, coupling means adapted when theendless fiexible means is driven unidirectionally automatically tocouplethe carriage to an advancing one of -said runs for controlledadvancing movement of the carriage and nozzle tube and to the other run,which constitutes a return run, for controlled return movement of thecarriage and nozzle tube, the endless flexible means being substantiallyinelastic,` said coupling means comprising-frst abutmentmeans providedon the carriage, a driving element projecting laterally` Vfromthe-flexible means and arranged to engage the first abutment means inthe advancing run of the chain, said driving element being arranged todisengage froml the first abutmentmeans at or after the end of theadvancing movement and to travel around awheel at the end of the saidrun, and second abutment means providedron the carriage spacedlongitudinally and rearwardly of the first abutment means to'provide adwell period for the nozzle tube in its extreme positions, said secondabutment meansrbeing arranged to be engaged by said driving element'inthe return run of the exible means, the driving element being arrangedto disengage from the second abutment means during movement around afurther wheel atthe end'of the return run. 'Y

2. In a fluid heater cleaner as Vclaimed-in claim l, a braking abutmenton the carriage spaced between said first and second abutment means, andcoacting braking abutment means on the flexible meansyfor theretardation of forward movement of the nozzle tube during periods whenthe nozzle tube is to be moved forwardly and is biased forwardly by theVpressure ofl cleaning Huid supplied to its interior, andmeans fordiverting said coacting braking abutment means on the exible means' andsaid driving element around said Ybraking abutment on thecarriageduring'their movements in the area 0f said fur- 'therwheel.

3. A fluid heater cleaner 'as claimed in claim 2,'Wherein said coactingabutment means on the exible means projects laterally from the flexiblemeans and -is so spaced upon the ilexible means from the driving elementthat advancing movement of the-carriage at a speed exceeding that oftherexible elementwhich results in disengagement of the driving elementfrom the first abutment means is followed in quick succession byengagement of the brakingv abutment with the coacting braking abutmentmeans on the flexible means, the coacting braking abutment means on theflexible meansbeing so dimensioned that itis able to pass the first andsecond abutmentmeans on the carriage.

y 4. A fluid heater cleaner as claimed in claim 3, wherein the drivingelement and said braking abutment means on the flexible element eachcomprise extensionsqxed 'to and projecting from the flexible means, andeach abut- :ment means on 'the carriage includes a kfork havingbifurcations forengagement with respective extensions.

. 5. A uid' heater cleaner fasclaimed in claim 1, wherein one of saidwheels is a driving wheel and the other of said wheels is an idler wheelspaced from the driving wheel along'the track, jockey wheels arrangedrespectively adjacent the driving wheel and the idler wheel and engagingthev endless flexible meansto cause the two runs to lie closely adjacentone another, and the carriage is provided with locating means adapted toengage the runs and maintain proper lateral positioning thereofrelatively to the abutment means.

6. A fluid heater cleaner as claimed in claim 5, including means at oneend of the track for mounting said end ofthe track against a fluidheater with the rest ofthe track projecting therefrom, the driving wheelbeing disposed ator adjacent said end of the track.

7. A fluid heater cleaner having a nozzle tube axially reciprocable toadvance the tube from a retracted po'sition and to withdraw the tube tothe retracted position and connected to a carriage movable to and froalong a track and operating mechanism for reciprocating v the nozzletube and carriage, wherein the operating mechanism includes endlessflexible meanshaving two' runs extending longitudinally of the track,unidirectional Vdriving means for actuating said exible means, andcoupling means adapted when the endless flexible means isdrivenunidirectionally automatically 4to couplethe carriage to one run forcontrolled movement of the carriage'and nozzle tube in one direction andto' the other run for controlled movementv of the carriage and nozzletube in the opposite direction, and wherein the endless fiexible meansdrives power transmission means on the carriage to rotate the nozzletube, said tube during retraction being rotated in the same sense asduring advancement so' that during the retraction the discharge ofcleaning fluid sweeps through a helical path different fromthat overwhich the discharge sweeps during the advancement.

8. A fluid heater cleaner as claimed in claim 7, wherein the runs of theendless exible means are coupled with respective actuating wheels on thecarriage and the actuating wheels are coupled with the nozzle tube forrotation thereof through means permitting each wheel to be driventhrough relative movement between the run asso'- ciated therewith andthe carriage while the other actuating wheel is stationaryV about itsaxis.

9. A fluid heater cleaner as claimed in claim 8, wherein each actuatingwheel is coupled to the nozzle tube through a free-wheel device and agear wheel to a common gear wheel.

l0. A fluid heater cleaner `as claimed in claim 9, the common gear wheelbeingvcoupled with the nozzle tube through an intermediate bevel wheeland a bevel wheel coaxial with the nozzle tube.

ll. A fiuid heater cleaner as claimed in claim 8, wherein associatedwith each actuating wheel are two jockey pulleys which serve to causethe endless flexible means to embrace a suitable arc of the actuatingwheel'and maintain proper lateral positioning of the'associated run atopposite sides of the actuating wheel relatively to the carriage.

References Cited in the file of this patent UNITED STATES PATENTS1,239,909 Hards Sept. ll, 1917 1,611,854 Damrow Dec. 2l, 1926 2,324,785Linaker July 20, 1943 .2,520,187 Wilshusen et al.. Aug. 29, 19502,760,222 Anderson Aug. 28, 1956 FOREIGN PATENTS 83,796 Norway 'June s,1954

